Washing apparatus and method



March 3,. 1970 M. K: MEHTA 3,493,339

7 WASHING APPARATUS AND METHOD Fi] .ed Jan. 31,1967

mvsm'osz MAHARAJ K. MEHTA 'BY ATTORNEYS United States PatentO 3,498,839 WASHING APPARATUS AND METHOD Maharaj K. Mehta, Cardilf, Glamorgan, Wales, assignor to P. Leiner & Sons (Encapsulations) Limited, Treforest, Glamorganshire, Wales, a British company Filed Jan. 31, 1967, Ser. No. 612,891 Claims priority, application Great Britain, May 12, 1966, 21,199/ 66 Int. Cl. B08b 3/02; B67c N04 US. Cl. 134-25 8 Claims ABSTRACT OF THE DISCLOSURE A three-stage washing apparatus comprising an inclined cylinder with an internal helix for drawing particles through a bath of liquid, through liquid introduced above the bath and collecting above the turns of the helix, and through a spray of liquid.

The invention relates to an apparatus for washing particles such as filled gelatine capsules.

During the formation of one-piece soft gelatine capsules, containing pharmaceuticals, and medicines, for example, the capsules become covered with a layer of edible lubricating oil. It is desirable to rinse the capsules in a liquid such as naphtha, in which the oil is soluble. To remove the oil completely the washing should be carried out in more than one stage. Use of the invention provides a three-stage continuous washing process for this purpose.

According to the present invention there is provided an apparatus for washing particles including an inclined rotatable cylinder with an internal helical flange or helix for drawing capsules up the cylinder, means for maintaining a bath of washing liquid in a lower section of the cylinder so that capsules drawn through this section of the cylinder will be submerged in the contained washing liquid, an inlet for the introduction of washing liquid to an intermediate section of the cylinder so that capsules drawn up this section of the cylinder will be submerged in washing liquid collected between the turns of he helix and the cylinder wall and an inlet for the introduction of a spray of washing liquid to an upper section of the cylinder which has a drained surface so that capsules drawn up this section of the cylinder will be rinsed under a spray of the washing liquid which drains off the capsules continuously.

The upper section of the cylinder wall may be perforated to provide the drained surface and the washing liquid from the inlets may enter through the perforations.

There is also provided a method for washing capsules in which the capsules are carried on the internal helical flange of a rotating cylinder through three sections of the cylinder in which they are successively submerged in a bath of washing liquid, submerged in washing liquid introduced to the cylinder above the bath and collected above the turns of the helix and passed over a drained surface under a spray of the washing liquid.

An embodiment of the invention will be described with reference to the accompanying drawing which is a cross section of an apparatus for washing gelatine capsules.

There is shown in the drawing a washing apparatus having an inclined cylinder 1 whose wall has perforations 2 and carries an internal helical flange 3. The cylinder is fixed to a central shaft 4 which is supported at either end in an outer casing 5 resting on a stand 6 by bearings 7. The shaft and cylinder are rotated by a motor 8 through a belt 9.

3,498,839 Patented Mar. 3, 1970 The lower section A of the cylinder 1 dips into a tank 10 of naphtha (the washing agent). The tank could be replaced by a bath retained in the end of the cylinder. The bath is cooled by the refrigerating coil 11 of a Freon compressor 12.

Gelatine capsules 13 enter the lower end of the cylinder by way of an inlet chute 14 and are drawn up the cylinder by the rotation of the cylinder. Part of the loWer section A and an intermediate section B of the cylinder have an unperforated sleeve 15. The inlets 16 and 17 in the wall of the casing 5 provide a supply of naphtha which is sprayed on to the ascending capsules through the perforations 2 in the inclined cylinder. A large portion of the spray of the lower inlet 16 falls within the intermediate section B of the cylinder inside the unperforated sleeve 15. This portion of the spray collects in the trough 18 formed between each turn of the helix 3 and the sleeve 15. The capsules, which have already been washed once as they were raised through the bath 10 are thus washed a second time by being submerged in the collected spray V of the lower inlet 16.

As the capsules are drawn up the cylinder beyond the part within the unperforated sleeve 15 to an upper section C of the cylinder where the naphtha can drain off through the perforations 2 in the cylinder Wall, they pass through the remainder of the spray from the lower inlet 16 and under the upper inlet 17. This provides a naphtha rinse in which the rinsing naptha drains off through the perforations 2, and down the inside of the outer casing 5 to the bath 10. The used naphtha passes from the bath 10 through an overflow pipe 19 in the outer casing 5, which maintains a constant level of naphtha in the bath, to a used naphtha tank. The used naphtha is piped to a distillation plant for redistillation and reuse. An agent such as lecithin may be added to the naphtha to prevent the capsules sticking together and to the cylinder wall. The lecithin may be drip fed into the bath by a drip-feed 20 or may be added to the naphtha supply.

Slugs, or empty capsules, are formed during the production as when the injection of the fill material of the capsules is cut off to rectify production defects. It is desirable to segregate these slugs before packaging the washed and dehumidified capsules.

The size of the perforations is chosen so that the slugs formed during production, which have a smaller volume than the full capsules, will pass through the perforations either above or below the sleeve 15. The slugs 21 passing through the perforations above the sleeve will then slide down the inner wall of the casing 5 and drop into a tray or strainer 22 immersed in the bath and extending so as to catch also the slugs 23 dropping through the perforations below the sleeve.

I claim:

1. A three-stage washing apparatus including:

an inclined cylinder comprising,

a lower section,

an intermediate section, and

an upper section, said upper section having a drained surface;

support means for rotatably supporting said cylinder in an inclined disposition;

drive means for rotating said cylinder about its axis;

a helical flange attached to the internal wall of said cylinder;

means for maintaining a bath of liquid in said lower section of said cylinder, and inlets for admitting washing liquid to said intermediate and upper sections of said cylinder, said inlets comprising spray means, and said drained surface of said upper section preventing accumulation of washing liquid; and

said intermediate section having a surface impermeable to washing liquid whereby said liquid accumulates adjacent the upper sides of the turns of the helical flange.

2. A Washing apparatus according to claim 1 in which said drained surface of said upper section comprises a perforated surface.

3. A washing apparatus according to claim 2 in which said impermeable surface of said intermediate section comprises a perforated surface continuous with said perforated surface of said upper section, and an unperforated sleeve surrounding said perforated surface of said intermediate section.

4. A three-stage washing apparatus according to claim 1, in which the inclined cylinder comprises an elongated, hollow cylindrical member provided With perforated walls throughout the upper and lower section thereof, said helical flange in said intermediate section having a continuous imperforate surface whose outer edge is joined to and is in continuous contact with the internal Wall of said cylindrical member with the upper sides. of said helical flange defining with said cylindrical member a fluid-retaining trough for receiving liquid from the inlet associated with said intermediate section to form a second bath above and isolated from the first-mentioned bath by a portion of said helical flange.

5. A three-stage washing apparatus according to claim 4, further including a stationary housing surrounding said elongated cylindrical member and extending throughout a substantial portion of the length thereof; and

said means for maintaining a bath of liquid in said lower section comprising a tank positioned adjacent the lower section of said cylindrical member and fixedly interconnected to said housing, the interior of said housing being in communication with the interior of said tank.

6. A method of washing capsules comprising transport ing the particles by an inclined helix through three successive zones comprising,

passing said capsules through a bath of Washing liquid in said first Zone,

submerging said capsules in a bath of washing liquid in said second zone and passing said capsules and bath through said second zone and passing said capsules through a spray of washing liquid in said third zone.

7. A method of washing according to claim 6 further comprising passing said capsules in said third zone over asurface having perforations such as to pass unfilled capsules and retain filled capsules.

8. A method according to claim 6, in which the second-mentioned bath is isolated from the first-mentioned bath and in which the capsules and bath are moved in the same direction through said second zone in a direction away from the first zone following which the washing liquid forming the second bath is separated from the capsules.

References Cited 3 UNITED STATES PATENTS 697,272 4/ 1902 Plummer 13425 XR 1,374,341 4/1921 Vaudreuil 134-25 XR 2,299,080 10/ 1942 De Back 134--25 XR FOREIGN PATENTS 471,507 2/ 1951 Canada.

538,510' 10/1931 Germany.

JOSEPH SCOVRONEK, Primary Examiner D. G. MILLMAN, Assistant'Examiner US. Cl. X.R. 1346 5, 132, 133 

